Associate Program 4: Antileishmanial, Anti-trypanosomal, and Anti- trichomonad drug Discovery and Development take the ethnomedical, and later, ethnobotanical leads stepwise through in vitro bioassay guided purification of the active principles from medicinal herbs. Then follows with structure versus anti-parasite activity using either botanically related plants to those found active or pure compounds postulated to inhibit via a similar mechanism to that of the plant under study. Finally, this program guides the testing of the purified products, anti-parasite drug candidates through preliminary efficacy testing in rodents and higher animals and the collateral animal tests for undesirable toxicity. This program is structured to carry the ethnomedical "lead"compound through all stages of preclinical testing.